写出三种表示目的状语的动词不定式的形式

写出三种表示目的状语的动词不定式的形式

动词不定式作目的状语主要有以下三种结构形式：
1. to do … 这种结构形式可置于句首（为了强调目的时，通常把动词不定式放在句首）或句尾，通常不必用逗号隔开。在句首时通常译为：为了……；在句尾时通常译为：以便……，为了……，来……。如：
① I sat in the front of the bus to get a good view of the countryside.
② To master English, you must make much effort on it.
2. in order to do … 这种结构形式更能突出目的性，可以置于句首；也可以置于句尾。如：
① In order to get a good command of English in the shortest possible time, I am determined to work harder than before.
② She studies harder in order to catch up with her classmates.
3. so as to do … 这种结构形式也是为了突出状语的目的性，与第二种结构形式所不同的是它不能置于句首，只能置于句尾。如：
① The worker always gets up early so as to catch the first bus.
② He worked hard so as to pass the exam.
注：表示否定目的通常用not to do, in order not to do和so as not to do。如：
① Not to be noticed, he sat at the back of the room.
② He left his gun outside the house in order not to frighten his wife.
③ He came in quietly so as not to wake the child.